Method and apparatus for applying materials to surfaces



9ct. 16, 1934. L. G. MERRlTT-Er AL 19977321 METHOD AND APPARATUS FORAPPLYING MATERIALS TO SURFACES Filed June 5. 1931. 4 Sheets-Sheet lINVENTORS.

Oct. )16, 1934. L. G MERRITT ETAL 1,977,321

METHOD AND APPARATUS FOR APPLYING MATERIALS T0 SURFACES Filed June 5.1931 4,*Sheets-Sheet 2 JNVENTORS a, M Y I ATTORNEYS.

' @et 16, i934. IL, G| MERRITT EfAL 1,977,321

METHOD AND APPARATUS FOR APPLYING MATERIALS TO SURFACES Filed June 5.1931 4 Sheets-Sheet. 3

INVENTORS. Y

Oct. E6, 1934. L. G. MERRITT ET AL 1,977,321

METHOD AND APPARATUS FOR APPLYNG MATERIALS TO SURFACES Filed June 5.1951 4 Sheets-Sheet 4 :9 INVENTORS. M Amm M Patented Oct. 16, 1934METHOD AND APPARATUS FOR APPLYING MATERIALS TO SURFACES Louis G. Merrittand Ericsson H. Merritt, Lockport, N. Y., assignors, by mesneassignments, to Laminating Patents Corporation, Seattle, Wash., acorporation of Delaware application .time 5, i931, serial No. 542,257

l2 Claims.

This invention relates to methods and apparatus for disseminatingpowdered materials,and, more particularly, for the application ofpowdered materials to surfaces of articles such, for example, as veneersheets and the like.

An object of the invention is to provide improved methods and apparatusof the character under consideration.

Another object is to provide a method whereby powdered materials may beapplied to surfaces of articles in a particularly uniform manner.

A further object is to provide a method whereby powdered materialscontaining particles of varying sizemay be readily, effectively anduniformly applied to surfaces of articles, and particularly to surfacesof moving articles.

Another object is to provide apparatus of the character underconsideration for readily and elfectively applying powdered materials tothe surfaces of articles.

Another object is to provide apparatus of the character underconsideration whereby powdered materials may be applied to the surfacesof articles in a particularly uniform manner.

Another object is the provision of improved means for applying powderedmaterials tothe surfaces of moving articles.

Another object is to provide means for eifectively applying to thesurfaces of articles a powdered material containing particles of varyingsize.

An additional object is the provision of .apparatus of the characterindicated which is relatively simple in construction, which can bereadily assembled, and in which parts may be readily removed for repairand replacement: which will operate in a particularly uniform marmer,and which will eciently accomplish the purposes for which it isintended.

Other objects of the invention will in part be Jbvious and will in partappear hereinafter.

The invention accordingly'comprises the several steps and the relationand order of one ir more of such steps with respect to each of ;heothers, and the apparatus embodying fea- ;ures of construction,combinations of elements md arrangement of parts, all as exemplified inyhe'following detailed disclosure, and the scope if the application ofwhich will be indicated in `he claims.

For a fuller understanding of the nature and bjects of the inventionreference should be lad to the following detailed description taken nconnection with the accompanying drawings, n which:

Figure 1 is a view of a form of apparatus-exemplifying the invention invertical section along the line 1-1 in Fig. 3;

Fig. 2 is an enlarged detail showing of the 60 central portion of Fig.1; Y

3 is a view at right angles to Fig. 1 in vertical section along the line3-3 in Fig. 4; and

Fig. a is a side view of the apparatus.

The problem of applying powdered material to surfaces of articles, as,for example, in applying coating materials inl powdered form or inapplying powdered adhesive materials to surfaces to be glued has proveda matter of considerable4 dimculty, particularly in instances wherein anespecially high degree of uniformity in the spread of the powderedmaterial on the surfaces was desired. 'I'hat there are many suchinstances will be readily apparent when it is considered that theappearance of coated articles often depends upon the uniformity of thecoating applied, and that in the gluing art the strength of the bond isoften dependent upon a high degree of uniformity of. spread. Again,-where the coating material or the adhesive material is of a relativelyexpensive nature the desirability of limiting the spread to a minimumthroughout the entire area of the surface to which the material isapplied will be readily apparent.

With the foregoing and otherends in View, the present inventioncontemplates the provision of methods and means whereby various factorshav ing tendencies away from a maximum of uniformity may be desirablycontrolled and various diiiiculties overcome.

vThe invention pnovidesfmethods and mea'ns in the performance and use ofwhich more orless of a varietyof desirable steps may be performed in adesired sequence. While in the more specie aspects of the invention,all, or at least several, of such steps will :be performed, theinvention in its broader aspects is not limited to the performance of a.method involving, or the use .of apparatus for performing, anyparticular num- 100 ber or sequence of such steps.

As an example 4of a methodsuch as contein-V plated -by the inventionreference may be had to a procedure which may be conducted by the ap-'paratus hereinafter described, and which involves continuouslydisseminating above moving articles, such as veneer sheets or the like,a stream of particles substantially as wide as the sheets,

breaking up the stream so-as'to assure thatV the particles will not beassociated in globules or in. 111111.01.' streams, and directing a.current of air against the broken-up stream,` so as to carry par.-

ticles evenly and regularly onto the moving sheet. Where the particlesto be disseminated are contained in a receptacle, it is'desirable toreplenish f the particles continuously and. preferably at a controlledand substantially uniform rate, and

it is also desirable that lthe particles 1to ybe sup-r plied beagitatedl in many instances One form of apparatus such as contemplatedby the invention and such as utilizable in carry-f ing out the methodscontemplated by the inven tion isr exemplified in the drawings.

This apparatus comprisesja.r container l0 yfor holding a massof powderedmaterial, across the bottom of which there extends a portion of anendlessbelt 11 of `forarninate construction. Such a belt may desirablybe formed of cloth or wiremesh and is adapted to be supported on a plate12 which is preferably formed of .rubber firmly vulcanized toia platel13 carried by the framework of* the machine. 'line belt is adapted :topass into the container -undera bar y11i on aside plate 15 and: aftertravellingbeneath a mass of particles 16 in the container andreceiving'such,

particles in itsinterstices-r passes out of the container between thebevelledend 17 of the 'plate' i2 and a rubber cylinder i8 on arolleri9.A In' order to assure that the`r powdered material will drop outoflthe interstices of the belt as the latter clears the end l'l of theplate l2, therer ispro-'f vided a vibrator roller 20, the periphery-ofwhich is formed with protuberances 2l which are adapted dwing-rotationt0 jai the belt which is heldr tight lby means; hereinafter to ybeexemplied.

f .in order to assure that only the particles withinl the interstices ofthe belt will lbe carried from lthe contairner,y the roller 19 isrotated, preferably relatively slowly,. in a direction such that itssurface will move inwardly andA upwardly'as it entersA l the container,amd in order to prevent particles which are desirable for use in theformation of plywood and similar procedures the particles of thematerial will have a tendency more or less to cohere, and for thepurpose of breaking up globules thus formed, as well as for otherpurposes including the smoothing out of any unevenness in the film orstream of particles, a suitable break-up element is disposed in the pathof movement of the particles. As exemplified, this element consists of arotatable roll 25 having its downwardly moving side in the path of thestream of particles falling from the points where the belt leaves theedge 17 of the support 12. It is to b'e noted that the particles tend tofollow an arcuate course along the side of this roll due to the naturalinduction of the air surrounding the roller.

The diiculties in providing a spread having a high degree of uniformityattend especially a procedure wherein the size of the particles to besprayed is irregular, i. e. where the material to be spread consists ofboth coarse and ne particles. This is not only the case wherein amixture of two materials of relatively different size is utilized; butalso in all cases where it is desired to avoid the necessity of using apowder of which the particles are of substantially the same size,

with the attendant expense and waste involved 1ny the lprovision of sucha powder.

` In order to avoid the tendency of casual air currents to vary themovement of. theparticles beneath the roll 25y and tor separate thefiner particles from the coarse-r as well as to dissipate certain of thefiner particles, and also in order to Aguider the .particles in an evenand substantially uniform manner in a desired direction toward thesurface to be coated there is providedmeans for ejecting a jet of airagainstthe. stream at a point ldownwardly soA as todirect a current ofair, just under the roller 25, in a direction transverseto the f streamof the falling particles and. downwardly, with the result that theseparticles will assume courses generally between a sharply inclinedr y;

plane anda less inclined plane above the same,

'the' heavier particles following a course adjacent the sharply inclinedplane, and the lighterparf ticles following a course adjacent the lessinclined plane. f A current of. air is carried into the nozzle member 27from a blower' 3l at oneside of: the machine through a `conduitcomprising opening .'Bla, dampening chamber 31h and opening 32.

The current is smoothed out tol provide; an even outward how throughoutthe length of the space between'the plates 28 and 29 by meansl of barilemembers 32a extending transversely. of the nozzle member .27..y f y Thecurrent of air issuing from between'the members 28 and 29 provideslalmovinginclined support. on which the particles toboggan" to thsurface on which they are to be'spread. f

It is desirable that lthe velocity of lthis air` l current be justenough to overcome the tendency of natural or prevailing air-currents toinfluence the falling powder. For example, under conditions where noextraneous air currents are set up outside the machine a desirablevelocity, at the point where the air leaves the nozzle portion may beabout feet per minute for 200 mesh particles, may be from to 200 feetper minute for material 90% of which would pass through 100 mesh andLl0% of which would pass through 150 mesh; and may be 230 feet perminute for material all of which would pass through 80 mesh and 30% ofwhich would pass through 150 mesh and which contained a relatively smallpercentage of i'lnes. rllhe foregoing gures are apparent velocities,based upon readings of an anemometer (Tycos No. A105, outside diameterof the blade circle 3% inches, inside diameter 1% inches, width of blade.one inch on outside circle and il inch on inside circle) placed withits center particles have different weights; a higher velocf ity beingused with powders having a greater Weight per particle.

The surfaces of the articles upon which the particles are to be receivedmay be arranged in any 'desired manner for the reception of these Theparticles referred to are those of an through the path of flow of theparticles, as, for example, on a suitable conveyor. In the presentinstance, there is provided a conveyor 33 arranged to move sheets 34 ofveneer or the like along a plane which is relatively close to the roll25 and through the cloud of particles indicated at 30.

The surfaces may be moved in any desired dlrection with respect to thedirection in which the particles are carried by the air current. In thepresent instance, the movement of the sheets is exemplified as being ina direction opposite to the horizontal component in the direction ofmovement of the particles. Such an arrangement is of advantage incertain instances, as, for example, when relatively non-coherentparticles are being applied to a relatively adherent surface, forinstance, a moist surface, since the finer particles will rst contactwith the adherent surface. Eective results, are secured, however, in alarge number of instances when the direction of movement of the sheetsis the same as the horizontal component of the direction of movement ofthe particles.

It will accordingly be seen that the present invention is of value incarrying out various gluing 'methods such, forexample, as 'thatdisclosed in the application of Theodore Williams Dike, filed February28, 1931, Serial No. 518,944, and which has matured into Patent Number1,869,957, issued August 2, 1932.

Powdered material may be supplied to the container 10 in any suitablemanner, but is prefer-l ably supplied thereto at a uniform rate and incontrolled amounts.. To this end there is provided at a point above thecontainer a trough-like container 35, the bottom wall of which isprovided by a plate 36 having formed at one side of its center line aseries of openings 37, and above the plate 36 there is disposed anadjustable plate 38 having a series of similar openings 39 adapted tocoincide with the openings 37. For the adjustment of this plate there isprovided a handwheel 40 carrying a screw 41 extending into a threadedopening in a bar 42 secured to the plate 38. Accordingly, by themovement of the handwheel the size of the channels provided by theopenings 37 and 39 may be reduced to any desired extent. l

Powdered material is supplied to the troughlike container from a hopper43, and movement of the powdered material past the openings, as well ascontinuous agitation of the material in the trough-like container isassured by causing a continuous circulation of the material as by meansof a pair of parallel oppositely-moving spiral conveyors 44 and 45.

The endless belt 11, which may be supported and driven in any suitablemanner, is, as exemplified, carried from the vibrating roll 20 over aroll 46 and thence over rolls 47, 48 and 49. Prior to passing into thecontainer. the belt passes over av roll 50. Between the rolls 49 and 50it passes inwardly about a tensioning roll 51, the shaft of which isjournalled in boxes 52 and 52', which are adapted to slide'betweenltrack members 53 and 54, and 53 and 54', respectively. A movement ofthe roll to eiect the tensioning of the belt may be. vcaused by theadjustment of a tension rod 55. It

is to be noted that in the construction indicated the roll 51 may bereadily slipped in place after the endless belt has been positioned overthe other rolls and may readily be removed merely by loosening asecuring means, such as the bolt and nut "attachment shown at 56. Thetension rods 55 are suitably fitted at their outer end to pass throughtension-adjusting wheels 57, which, acting through spaced sleeves 58,serves to bear against an equalizer bar 59. A weighted tension lever 60is suitably connected to the central portion of the equalizer bar 59 asthrough link pins 61, 62 and 63, link 64 and clevis 65. A shaft 66 isdisposed to pass between portions of the framework. The tension weight67 is attached to the lever 60 by means of gibs 68 in a manner whichallows for a wide vrange of movement of the ing articles-the airdelivery means. A combina tion of such elements provides a particularlyeffective means'for the spreading of powdered materials and especiallysatisfactory results have been found to be obtained by the use ofapparatus similar to that exemplified. However, in certain of itsbroader aspects the invention contemplates the provision of a variety offorms of apparatus embodyingone or more of the types of elements setforth and adapted for use in various ones of a wide number ofprocedures.

'I'he exemplified apparatus embodies a form of conveyor which has beenfound particularly de sirable for use in methods such as those underkconsideration. As exemplified, the conveyor 33 comprises a singleendless cable 70 extending back-and-forth over drums 71 and 72 which areprovided with annular grooves 73 for the reception of the cable.' Duringa portion of its run from4 one end of the drum 72 to the other end ofthe drum 71, the cable passes about'sheaves 74 and 75 which are carried,respectively, on brackets 76 and 77. 'I'he brackets are adjustablymounted between rails 78 and 79, and 80 and 81, respectively, so thatthey may be slid to a position to suitably tension the cable. adjustedposition by suitable means such as the nuts 82 and 83, respectively.ASuitable means (not shown) may be'provided for driving one or the otherof the drums 71.and 72; such means may include variable speed mechanismof any well-known type, if desired.

Suitable means are likewise provided for driving the other movableelements of the apparatus. In this connection it is to be noted that theforaminate belt or screenV preferably moves at a relatively slow speed,in certain instance, for example, two, three or four feet per minute. Itis desirable, in many cases, that variable speed mechanism be providedin the driving means for this belt so that the `quantity of materialdisseminated may be readily controlled.

' In the present instance there is provided a driving motor`106 from theshaft of which rotative motion is transferred by a sprocket 107, a chain108, and a sprocket 109 to the constantspeed shaft 110 oiv avariable-speed mechanism indicated generally at 111 and which may be ofany well-known type, as, for example, the coneand-belt type. On thevariable-speed shaft 112 of the variable-speed mechanism there iscarried .a gear 113 meshing With a reduction gear 114 They are held invSense.

carried for the sake of simplicity of construction on the shaft 110, inthe present instance, but freely movable thereon. Carried on the gear114 is a small gear 115 meshing with a secondary reduction gear 116which carries a sprocket 117 connected by a chain 118 with a sprocket119 rotatably mounted on'a stud 120. Carried on the sprocket 119 is asmaller sprocket 121 from which a chain 122 extends to a sprocket 123carried on the shaft of the drive roll 49 for the screen. There is alsocarried on the sprocket 119 a sprocket 124 from which a chain 125extends over a sprocket 126 carrying a gear 128 meshing with a gear 129mounted on the shaft of the doctor roll 19.

The shaft 110 also carries a sprocket 130 from which a chain 131 extendsto a sprocket 132 rigidly keyed to one of the ends of the break-up roll25. A second sprocket 133 rigidly mounted beside the sprocket 132imparts its motion through a chain 134 to a sprocket 135 rigidly fixedto one of the ends of the Vibrator roll 20.

The drive for the spiral conveyors is an independent unit in the presentinstance, due to the somewhat remote locations of these conveyors. Amotor 136 supported on a bracket 137 imparts its motion through acoupling 139 to a worm gear speed reducer 140 from which the reducedrotative speed is further conveyed to the' spiral conveyors'through asprocket 141, a chain 142 and a sprocket 143.

The term dry air as used herein is intended to refer to air to whichdroplets of moisture have not been added.

Since certain changes in carrying out the above method and in theconstructions set forth, which embody the invention may be made withoutdeparting from its scope, it is intended that all matter contained inthe above description or shown in the accompanying drawings shall` beinterpreted as illustrative and not in a limiting It is also to beunderstood that the following claims are intended to cover all of thegeneric and specific features of the invention herein described, and allstatements of the scope of the invention which as a matter of languagemight be said to fall therebetween.

Having described our invention, what we claim as new and desire tosecure by Letters Patent is:

1. The method of applying powdered material to a surface, whichcomprises causing a movement of the surface, directing generally towardsaid surface a stream of particles at a rate substantially just suicientfor the desired coating of the moving surface and'directing against saidstream a current of dry air moving in a direction transverse to saidstream and toward said surface and so regulated that material quantitiesof particles will not be removedfrom said surface by said current.

2. The method of applying powdered material to a surface, whichcomprises causing a movement of the surface, directing generally towardsaid surface a stream of particles at a rate substantially justsufficient for the desired coating of the moving surface and directingagainst said stream a current of dry air moving in a directiontransverse to said stream and opposite to the direction of movement ofsaid surface and so regulated that material quantities of particles willnot be removed from said surface by said current.

3. The method of applying powdered material to a surface, whichcomprises directing a curtain of particles in a given direction,breaking up any globules or independent streams of particles embodied insaid curtain, moving a surface beneath said curtain, directing againstsaid curtain a current of dry air in a direction generally transverse tosaid stream and toward the surface to be coated and in a manner suchthat substantially all the particles directed toward said surface willbe evenly deposited on said surface.

. 4. The method of applying powdered material to a surface, whichcomprises causing a relative movement of a container for powderedmaterial and a surface to be coated, supplying a continuous controlledow of particles of material to said container, withdrawing material fromsaid container at a uniform rate substantially just suncient for thedesired coating of a surface during such movement, directing thewithdrawn particles in a stream toward the surface of an article to becoated, and guiding the iiow of particles toward said surface bydirecting against said stream la current of dry air so regulated thatmaterial quantities of particles will not be removed from said surfaceby said air current.

5. Apparatus for applying powdered material to surfaces comprising meanscontinuously to measure out uniform quantities of powdered materials andto uniformly discharge measured amounts of material from the measuringdevice,

means to separate the individual particles of the material sodischarged, and means for directing a current of dry air upon theseparated particles whereby said particles are guided to a surface to beglued.

6. Apparatus for applying powdered material to surfaces, comprisingmeans including an endless foraminate belt to disseminate a powderedmaterial, and means to guide the disseminated material toward thesurface of an article.

7. Apparatus for applying powdered material to surfaces, comprisingmeans including an endless foraminate belt to disseminate a powderedmaterial, and means to direct a current of air relative to thedisseminated material toguide the same toward the surface of an article.

8. Apparatus for applying powdered material to surfaces, comprisingmeans to disseminate a powdered material, said means including anendless foraminate belt and a rotary vibrator member, and means to guidethe disseminated material toward the surface 'of an article.

9. Apparatus for applying powdered material to surfaces, comprisingmeans providing a container for materials, means including an endlessbelt'for withdrawing materials from lsaid container, means including aVibrator member to remove withdrawn materials from said belt, and meansto direct the withdrawn materials against a surface to be coated.

10. Apparatus for disseminating powdered materials, comprising a'nendless foraminate belt, means to cause said belt to receive powderedmaterial in the openings thereof, and means to remove powdered materialsfrom the openings in said belt.

11. ApparatusA for disseminating powdered materials, comprising anendless foraminate belt, means to cause the belt to receive powderedmaterial in the openings thereof, and means to vibrate the belt to causethe removal of particles from said openings.

12. Apparatus for disseminating powdered materials, comprising anendless foraminate belt, means for maintaining a mass of material abovea portion of said belt, means to drive said belt,

and means tp cause materials received in the openings of said belt tofall therefrom at a given point in its path.

13. Apparatus for disseminating powdered materials, comprising anendless foraminate belt, a supporting surface for a portion of saidbelt, means tovprovi'de the side-walls of a container above saidsupporting surface, means to drive said belt, and means to cause thematerial received by said belt in the openings thereof to fall therefromat the point where said belt leaves said supporting surface.

14. Apparatus for disseminating powdered materials, comprising anendless foraminate belt, a supporting surface for a portion of saidbelt, means to yprovide the side-wallsl of a container above saidsupporting surface, said means including a doctor roller disposed withits periphery adjacent one edge of said supporting member, means todrive said belt, and means to cause the material received by said beltin the openings thereof to fall therefrom at the point where said beltleaves said supporting surface.

15. Apparatus for disseminating powdered materials, comprising anendless foraminate belt, a supporting surface for a portion of saidbelt, means to provide the side-walls of a container above saidsupporting surface, said means including a doctor roller disposed withitsv periphery adjacent one edge of said supportingmember, means todrive said belt, means to-drive said doctor roller in a direction suchthat its periphery moves rearwardly with respect to said endless belt,and means to cause the lmaterial received by said belt in the openingsthereof to fall therefrom at the point where said belt leaves saidsupporting surface.

16. Apparatus for applying powdered materials to surfaces includingmeans to move a surface in a given path, means to disseminate a powderedmaterial, and means to provide a low velocity current of dry air todirect the powdered material upon said surface.

17. Apparatus for applying powdered `materials.

to surfaces including means to move a surface in a given pathmeans tocause a flow of material in a curtain toward said path of movement, andmeans to direct against the flowing material a current of dry air movingtransversely to the curtain and toward said path of movement.

18. Apparatus for applying powdered materials to surfaces includingmeans to move a surfacein a given path, means to' cause a continuous nowof powdered material in a given plane, means interposed in the path offlow of said material for breaking up any aggregations of particles anddelivering the particles in a single stream, and means for directing' acurrent of dry air against the delivered stream whereby the particlesmay be directed against the moving surface.

vet

19. Apparatus for applying powdered materials to surfaces includingmeans to move a surface in a given path, means to cause a continuous owof powdered material in a given plane', means interposed in the path offlow of said material for breaking up any aggregations of particles anddelivering the particles in a single stream, and means to direct aslowly moving current of dry air against the said stream to direct theparticles against a surface.

20. Apparatus for applying powdered materials to surfaces includingmeans to move a surface in a given path, means to cause a flow ofmaterial in a curtain toward the path of said movement, and means todirect against the owing material a current of dry air moving in `adirection toward moving surface and opposite to the direction ofmovement thereof, said directing means being arranged so that the aircurrent while moving in said direction contacts said flow on its way tosaid pathr 21. Apparatus for applying powdered materials to surfacesincluding means to move a surface in a given path, means to cause acontinuousiiow of powdered material in a given plane, a break-up rollhaving its axis disposed at one side of the path of flow of saidmaterial and having one side of its periphery in said path of flow,means to' rotate said break-up roll with said side moving in for aportion of said belt, means to provide the side-walls 'of a containerabove said supporting surface, means to drive said belt, and means tocause the material received by said belt in the openings thereof to falltherefromv at the point lwhere said belt leaves said supporting surface;

means interposed in the path of flow of said material for breaking upthe same; and means for directing the broken-up material against themoving surface.

23. Apparatus for applying powdered material to surfaces, comprisingacontainer, means for supplying a continuous controlled flow of particlesof material to the container, means for withdrawing material from thecontainer at a uniform rate,` and means for controlling the ow ofparticles toward a'surface and including means for supplying a lowvelocity particle-guiding current of dry air.

24. The method of applying powdered material to a surface, whichcomprises causing a movement of the surface directing generally towardsaid surface a curtain of particles extending transversely of thedirection of movement of said 120,.

surface, and directing against said curtain along a line above saidsurface a current of dry air moving in a direction transverse tovsaidcurtain and toward said surface -to alter the course of the particles inthe general direction of the current, 12 the course of the finerparticles being altered to a greater extent than the course of thecoarser particles.

25. The method of applying powdered material to a surface, whichcomprises causing a movement of the surface, directing toward saidsurface a curtain of particles extending transversely of the directionof movement of said surface, and directing against said curtain along aline above said surface a current of dry air moving at a low velocity ina direction transverse to said stream and towards said surface to alterthe l course of the particles in the general direction of the current,the course of the ner particles being altered to a greater extent thanthe course of the coarser particles. l 26. The method of applyingpowdered material to a surface, which comprises causing a curtain ofparticles to be delivered in a givenA direction, causing a relativemovement of said curtain and 145 a surface, and directing a slowlymoving dry air current in a direction transverse to said curtain andtoward `said surface to guide the particles of material to the surface.

27. The method of applying powdered material to a surface, whichcomprises causing a movement of the surface, directing a stream ofparticles generally toward said surface, and directing a current of dryair against said stream in a direction transverse to said stream andtoward said surface and in such manner that the particles will movetoward said surface at an angle thereto and will move over a coursefan-shaped in cross-section with the heavier particles at theside of thecourse nearest the point of entry of the air current.

28. Apparatus for applying powdered material to surfaces, comprisingmeans providing ancontainer, means including an endless foraminate beltfor withdrawing materials from said container, means to move a surfacealong a given path, means to remove particles of material from said beltand to direct a stream of the removed particles toward said path, andmeans to direct an air current against said stream and toward saidsurface.

29. Apparatus for applying powdered material to surfaces, comprisingmeans to move a surface in a given path, means to cause a transverselyextending stream of material to move generally toward said path, abreak-up roll interposed in the course of now of said stream,` and meansto direct a transversely extended dry air current against said streamimmediately below said breakup roll and in a direction transverse tosaid stream and toward said surface.

30. Apparatus for applying powdered material to surfaces, comprising ameasuring device, means to discharge measured amounts of material fromthe measuring device in a uniform curtain, means to separate anyaggregations of particles in the curtain into individual particles, andmeans to deliver upon the particles a current of dry air so regulatedthat `they will be guided through a free space above a surface anduniformly deposited thereon.

31. Apparatus for applying powdered material to surfaces, including anendless foraminate belt, a member contacting with the underside of saidbelt and having' a transverse edge, means to maintain powdered materialabove said belt at a point adjacent said member to ll the openings insaid belt, the last-mentioned means including a doctor member, means tomove said belt past said maintaining means and over said edge, and meansdisposed beyond said edge in the direction of movement of said belt forvibrating said belt and discharging the powder from the openings thereinat a point adjacent said 32. Apparatus for applying powdered material tosurfaces, including an endless foraminate belt, a member contacting withthe underside of said belt and having a transverse edge, means tomaintain powdered material above said belt at a point adjacent saidmember to ll the openings in said belt, the last-mentioned meansincluding a doctor member, means to move said belt past said maintainingmeans-and over said edge, means disposed beyondv said edge in thedirection of movement of said belt for vibrating said belt anddischarging the powder from the openings therein at a point adjacentsaid edge, a breakup roll disposed beneath said edge with its axisbeyond the same in the direction of movement of said belt, and means torotate said break-up roll in .a direction such that its side under saidedge moves downwardly.

33. Apparatus for applying powdered material to surfaces, including anendless foraminate belt,

a member contacting with the imderside/of said belt and having atransverse edge, means to maintain powdered material above said belt ata point adjacent said'member to fill the Vopenings in said belt, thelast-mentioned means including a doctor member, means to move said beltpast said maintaining Vmeans and over said edge, means disposed beyondsaid edge in the direction of movement of said belt for vibrating saidbelt and discharging the powder from the openings therein at a pointadjacent said edge, a break-up roll disposed beneath said edge with itsaxis beyond the same in the direction of movement of said belt, means torotate said break-up roll in a direction such that its side under saidedge moves downwardly, ymeans to move a surface in a path under saidbreak-up roll in a direction perpendicular to its axis, and means todirect in a plane just under said break-up roll and in a directionopposite to the direction of movement of its underside and downwardly acurrent of air having just sufficient velocity to guide the particlestoward a moving surface and deposit them thereupon.

34. Apparatus for applying powdered material to surfaces, includingmeans to provide a curtain of powdered material moving in a givendirection, a break-up roll disposed in the path of said curtain andarranged to receive the particles on a side thereof moving in thedirection of movement of the particles, and means to direct a current ofdry air in a plane just under said break-up roll and from the oppositeside thereof and downwardly.

35. Apparatus for applying powdered material to surfaces, comprisingmeans for moving a. surface along a path, means including an endlessbelt to provide a curtain of powdered material moving generally toward asurface moving along said pathVand means to direct against said curtaina current of air moving in a direction transverse to said curtain andtoward said surface and at a speed just vsunicient to guide theparticles to said surface.

36. Apparatus for disseminating powdered materials, comprising anendless foraminate belt, a supporting surface for a portion of saidbelt, means to provide the side-walls of a container above saidsupporting surface, said means including a doctor roller disposed withits periphery adjacent one edge of said supporting member, means todrive said belt, means to drive said doctor roller in a direction suchthat its periphery moves rearwardly with respect to said endless belt,and means to cause the material received by said belt in the openingsthereof to fall therefrom at the point where said belt leaves saidsupporting surface, said means including a vibrator member.

37. Apparatus for applying powdered material to surfaces, comprisingmeans to cause a transversely extending stream of material to movetoward the path of movement of a surface, and means to direct a currentof dry air against said stream along a line spaced from said path and ina direction transverse to said stream and toward said path, saiddirecting means being in such position that the air current while movingin said direction contacts the stream before it reaches said path.

38. Apparatus for applying powdered material to' surfaces, comprisingmeans to cause a transversely extending stream of material to movetoward the path of movement of a surface, and means to direct a lowvelocity dry air current -los powdered material may be withdrawn oversaid supporting surface, a doctor member for limiting the amount ofmaterial withdrawn by said belt, and means to cause the materialwithdrawn by said belt to fall therefrom at a point where said beltleaves the supporting surface, and means to direct a current of air uponthe stream of parti-v cles after it leaves the belt.

40. Apparatus for applying powdered. material to surfaces, comprising anendless foraminate belt, a supporting surface for a portion of saidbelt, means providing a container from which powdered material may bewithdrawn over said supporting surface, a doctor member for limiting theamount of material Withdrawn by said belt, means to cause the materialwithdrawn by said belt to fall therefrom at the point where said beltleaves the supporting surface, break-up means disposed in the path ofmovement of the falling particles, and means to direct an air current onthe particles after they are acted on by the break-up means.

41. Apparatus for applying powdered material to surfaces, comprisingmeans including an endless foraminate belt for continuously withdrawingquantities of material from a mass, means-including a vibrator memberfor discharging the withdrawn material in a curtain, and means to directa slowly-moving current of air against the curtain.

42. Apparatus for applying powdered material to surfaces, comprisingmeans to cause a curtain of particles to fall toward the path ofmovement of a surface, and means for directing a laterally extendedcurrent of dry air against one side of said curtain to guide theparticles to the surface, said directing means including a restrictedejection channel of substantially uniform extent leading rearwardly fromthe ejection opening.

LOUIS G. MERRIIT; ERICSSON H. MERRI'IT.

